This paper argues that during the 'golden' age of medical reform in the first half of the nineteenth century in the Cape Colony there was significant differentiation within the medical profession which contributed to a slow and uneven process of professionalization in spite of comprehensive and early legal regulation under one licensing body. Differences in permitted practice, settlement patterns, economic and organizational opportunities gave doctors in Cape Town, the colony's biggest and most important city, greater incentives and more scope to develop professional regulation and organization than those in the rest of the colony. A government Ordinance passed in 1807 gave regularly-trained medical practitioners a legal monopoly over medical practice, but did not initially prevent those practising outside Cape Town from selling both medicines and medical advice. Cape Town doctors thus enjoyed greater social differentiation from tradesmen and better legal control over competition from druggists and 'irregulars' than country practitioners. The difference between practitioners in Cape Town and elsewhere remained important even after new regulations removed legal distinctions in 1830. While country practitioners now sought tighter regulation over permitted practice they could not easily make common cause with the more powerful professional medical élite in Cape Town. This élite group had vested social and economic interests in maintaining their privileged status within the Cape profession, especially when threatened by local recession and political and economic competition from Eastern Cape doctors in the 1850s.